JP2002324834A - Electrostatic chuck device, laminated sheet for electrostatic chuck, and adhesive for electrostatic chuck - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrostatic chuck device and a laminated sheet for an electrostatic chuck capable of preventing the flatness deterioration of a wafer suction face and peeling of an adhesive layer from a ceramic substrate over a long time and superior in the heat dissipation of a wafer. SOLUTION: The electrostatic chuck device is provided with a metal base 10, a first adhesive layer 14 provided on the metal base 10 and a ceramic insulation board 16 provided on the first adhesive layer 14. The adhesive layers 14, 18 are one kind or two kinds selected from a butadiene-acrylnitril copolymer, olefin-based copolymer and polyphenyl ether copolymer and contain a hindered phenol-based anti-oxidizing agent.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrostatic chuck device for electrostatically attracting and fixing a conductor or a semiconductor such as a wafer, and a laminated sheet for the electrostatic chuck.

[0002]

2. Description of the Related Art In a process of processing a semiconductor wafer, a chuck device is used to fix the semiconductor wafer to a predetermined portion of a processing machine. There are mechanical, vacuum, and electrostatic chuck devices, but the electrostatic chuck device has an advantage that it can suck a non-flat wafer, is easy to handle, and can be used even in a vacuum. are doing.

An example of a conventional electrostatic chuck device is disclosed in Japanese Patent Publication No. 5-87177. This device is shown in FIG.
As shown in FIG. 1, an adhesive layer 2a, an insulating film 4b, an adhesive layer 2b, an electrode layer 3b made of a thin metal plate, an adhesive layer 2c, and an insulating film 4a are sequentially laminated on a metal substrate 1. Then, the wafer 5 is adsorbed on the insulating film 4a. A temperature control space 6 for controlling the temperature through constant temperature water or the like is formed in the metal base 1.

FIG. 7 shows an electrostatic chuck device disclosed in JP-A-8-148549. In this apparatus, a relatively thick insulating adhesive layer 2 is formed on a metal substrate 1, an electrode layer 3a made of a metal deposition film or a plating film is formed thereon, and an insulating film 4 is formed thereon. The semiconductor wafer 5 is adhered to the semiconductor wafer 5 by suction.

By the way, in these devices, the metal base 1
In order to ensure insulation between the electrodes 3a and 3b, the insulating layer provided between the metal substrate 1 and the electrodes 3a and 3b, that is, the adhesive layer 2a and the insulating film 4 in the example of FIG.
b, the total of the adhesive layer 2b, and in the example of FIG.
Must be formed sufficiently thick. Moreover, since these are all resin materials, their thermal conductivity is low, and as a result,
There is a problem that heat transfer from the wafer 5 to the metal substrate 1 is poor. Poor heat transfer can cause abnormal temperature rise of the wafer being processed.

Therefore, recently, a ceramic insulating plate having excellent insulation properties and better thermal conductivity than resin is disposed between the metal base and the electrode, thereby improving the insulation between the metal base and the electrode. It has been proposed to improve the heat transfer from the wafer to the metal substrate while maintaining a high level.

[0007]

Incidentally, the above-mentioned ceramic insulating plate is usually thin, and its lower surface is bonded to a metal substrate via an adhesive, and is also bonded to the upper surface of the ceramic insulating plate. An insulating sheet is attached via an agent. Conventionally, epoxy-based adhesives and the like have been used as such adhesives.However, since all adhesives more or less cause a volume change during the curing process, adhesives are particularly used at the outer peripheral portion of the ceramic insulating plate. The layer peels off from the ceramic insulating plate, deteriorating the thermal conductivity at the peeled part, making it difficult to cool the outer peripheral portion of the wafer, or applying stress to the ceramic insulating plate due to the volume change of the adhesive layer, There are various problems, such as distortion, the flatness of the wafer suction surface is deteriorated, the wafer suction force is reduced, and the leakage of the cooling helium gas supplied slightly between the wafer suction surface and the wafer becomes severe. Was. Also, if the adhesive layer formed on the upper surface of the ceramic insulating plate also undergoes a volume change in the course of curing, peeling occurs as described above, the ceramic insulating plate is distorted, and the flatness of the wafer suction surface is reduced. It causes the same to have an adverse effect.

Accordingly, the present inventors have proposed that by adding a rubber component to the adhesive layer provided on the upper surface or the lower surface of the ceramic insulating plate, the adhesive layer is given an appropriate elasticity and the adhesive layer has a volume change. It was also proposed that the elasticity relieves the stress even in the case of occurrence, and prevents distortion of the ceramic insulating plate and the wafer suction surface.

However, in such an adhesive layer containing a rubber component, the rubber component is degraded by oxidation during repeated wafer processing by plasma or the like, gradually loses elasticity, and the stress relaxation effect is reduced, and the rubber component is relaxed. The resulting stress causes distortion of the ceramic insulating plate and lowering of the flatness of the wafer suction surface, so that various problems as described above become apparent again.

The present invention has been made in view of the above circumstances, and can prevent the flatness of the wafer suction surface and the peeling of the adhesive layer from the ceramic substrate for a long period of time. To provide a good electrostatic chuck device and a laminated sheet for an electrostatic chuck.

[0011]

In order to achieve the above object, an electrostatic chuck device according to the present invention comprises a metal base, an adhesive layer provided on the metal base, and an adhesive layer provided on the adhesive layer. And a ceramic insulating plate made of ceramic, wherein the adhesive layer contains a rubber component and a phenolic antioxidant, and the rubber component is a butadiene-acrylonitrile copolymer, an olefin-based copolymer, And one or more selected from polyphenyl ether copolymers. Preferred examples of the phenolic antioxidant include a hindered phenolic antioxidant. Among them, one molecule has three or more phenol groups in which two or more t-butyl groups are bonded. However, a substance having a molecular weight of 700 or more is more preferable. In addition, hindered phenolic antioxidants contain 20
It is preferable that the thermogravimetric loss rate when heated to 0 ° C. is 5% or less, and the warp rate of each adhesive layer is 0.03% or less. Note that hindered means having steric hindrance.

On the other hand, the laminated sheet for an electrostatic chuck according to the present invention has an insulating film and an adhesive layer provided on at least one surface of the insulating film. A phenolic antioxidant, wherein the rubber component is one or more selected from a butadiene-acrylonitrile copolymer, an olefinic copolymer, and a polyphenylether copolymer. And An electrode may be fixed to the insulating film.

Further, the adhesive for an electrostatic chuck sheet according to the present invention contains a rubber component and a phenolic antioxidant, and the rubber component includes a butadiene-acrylonitrile copolymer, an olefin copolymer, and One or more kinds selected from polyphenyl ether copolymers, wherein the phenolic antioxidant has
A phenol group having two or more t-butyl groups bound to 3
It is a substance having at least a group and a molecular weight of at least 700.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described in detail. FIG. 1 shows an embodiment of the electrostatic chuck device according to the present invention. This electrostatic chuck device includes a metal base 10 having a disc shape, a first adhesive layer 14 having excellent insulating properties and stress relaxation properties, a ceramic insulating plate 16 having a disc shape, a second adhesive layer 18, and an insulating layer. Film 22 is formed in order, and the second adhesive layer 1
The electrode layer 20 having a certain pattern is formed between the insulating layer 8 and the insulating film 22. Further, a heat medium flow path 12 is formed inside the metal base 10 so that a heat medium for adjusting the wafer temperature is passed therethrough.

The electrode layer 20 is a metal deposition film or a metal plating film deposited or plated on the lower surface of the insulating film 22. The electrode layer 20 is connected to a voltage generator through a current supply unit (not shown) penetrating the second adhesive layer 18, the ceramic insulating plate 16, and the first adhesive layer 14, and when a voltage is applied to the electrode layer 20, Polarized charges are generated on the attracting surface of the insulating film 22, and the semiconductor wafer W is attracted. The object to be attracted by the electrostatic chuck device is not limited to a wafer, and any object can be attracted as long as it is a conductor or a semiconductor.

The insulating film 22, the electrode layer 20, and the second adhesive layer 18 constitute a laminated sheet 17 that is removed from the ceramic insulating plate 16 and replaced when the insulating film 22 is worn.

FIGS. 3 and 4 show this embodiment more specifically. As shown in these figures, three through-holes 24 are formed in the electrostatic chuck device so as to vertically penetrate the respective elements 10 to 22, and a lifting rod (not shown) is formed in these through-holes 24. The wafer W is raised and lowered by projecting the lifting rods upward from the wafer suction surface. Elements 10-1
8, a power supply member 27 such as a lead wire is connected to the electrode layer 20 via a connection portion 26 such as soldering.
The inside of the center hole 25 is sealed with an insulator 28 such as a resin. A voltage is externally supplied to the electrode layer 20 via the power supply member 27. The planar shape of the electrode layer 20 shown in FIG. 3 is an example, and various other modifications are possible.

As a material of the electrode layer 20, thin films such as copper, aluminum, tin, nickel, chromium, silver, palladium and alloys thereof can be easily formed by vapor deposition or plating, and wet etching can be performed. Any metal can be used as long as it is easy to form a pattern by the method.

The thickness of the electrode layer 20 is not limited.
It is preferably from 100 Å to 10 μm. If the thickness is less than 300 angstroms, it is difficult to form a uniform film, and if a highly reactive material such as aluminum is easily oxidized, it is difficult to maintain stable conductivity. On the other hand, when the thickness exceeds 10 μm, the formation cost is increased by the vapor deposition or plating method. In consideration of ease of manufacture, the thickness of the electrode layer 20 is 500 Å to 5 Å.
More preferably, it is μm.

The insulating film 22 is preferably an insulating film having a heat-resistant temperature of 150 ° C. or more in consideration of electric characteristics such as a dielectric constant ε, a dielectric loss coefficient tan δ, and a withstand voltage. Examples of the insulating film having a heat resistance of 150 ° C. or higher include, for example, a fluororesin (fluoroethylene-propylene copolymer or the like), polyether sulfone, polyether ketone, cellulose triacetate, silicone rubber, polyimide, and the like. Among them, polyimide is particularly preferable. Examples of the polyimide film include films sold under the trade names such as “Kapton” (manufactured by Dupont Toray), “Apical” (manufactured by Kanebuchi Chemical Industries), and “UPILEX” (manufactured by Ube Industries). Can be illustrated.

The thickness of the insulating film 22 is not limited, but is preferably in the range of 20 to 75 μm. From the viewpoints of thermal conductivity and adsorptive power, a thinner one is preferable, but in consideration of mechanical strength, withstand voltage and durability (fatigue resistance), 40 to 60 is preferred.
The range of μm is particularly preferred.

The ceramic insulating plate 16 needs to have excellent insulating properties and thermal conductivity and have resistance to solvents.
Specifically, alumina, aluminum nitride, silicon nitride, silicon carbide, zirconia, glass and the like are preferable, and those having a smooth surface are used. The thickness of the ceramic insulating plate 16 is not limited, but is preferably in the range of 0.3 to 8 mm, more preferably 0.5 to 4 mm, from the viewpoint of securing sufficient durability while releasing heat from the surface to be attracted. Optimally 0.5
２2 mm.

Metal substrate 10, first adhesive layer 14, ceramic insulating plate 16, second adhesive layer 18, insulating film 2
2, a plurality of gas passages (not shown) that are open to the wafer suction surface may be formed. By jetting a small amount of an inert gas, particularly a helium gas having excellent heat conductivity, through these gas passages, the cooling of the semiconductor wafer W can be promoted.

First adhesive layer 14 and second adhesive layer 18
As an adhesive for forming the insulating film 2
2. It is necessary that the electrode layer 20, the ceramic insulating plate 16 and the metal substrate 10 have excellent adhesive strength, electrical characteristics, and heat resistance to the four members. In particular, the first adhesive layer 14 has a stress relaxation ability. An adhesive having a high elasticity and a low Young's modulus is preferable. As such an adhesive having high elasticity, an adhesive containing a rubber component and a phenolic antioxidant is preferable. Particularly preferable as the rubber component is one or a mixture of two or more selected from butadiene-acrylonitrile copolymer, olefin copolymer, and polyphenyl ether copolymer, and particularly, butadiene-acrylonitrile copolymer. Coalescing is preferred. This is because the butadiene-acrylonitrile copolymer has appropriate elasticity and is excellent in the action of alleviating the stress applied to the ceramic insulating plate 16.

The phenolic antioxidant functions, for example, to absorb radicals generated by the rubber component when the adhesive layer is exposed to a high temperature, thereby preventing the rubber component from deteriorating. Agent Layer 14 and Second Adhesive Layer 1
8 prevents elastic deterioration. As such a phenolic antioxidant, a hindered phenolic antioxidant is particularly preferable. In particular, the phenolic antioxidant has three or more phenol groups in which two or more t-butyl groups are bonded, and has a molecular weight of 700 or more. More preferably, a compound having a molecular weight of 750 to 1500 is suitable. When this condition is satisfied, even when the electrostatic chuck device is exposed to a high temperature, the antioxidant effect hardly deteriorates,
This is because the effect of relaxing the stress of the rubber component can be maintained for a long time.

A particularly preferred adhesive is 10-90% by weight (more preferably 50-90% by weight, optimally 60-80% by weight) of a butadiene-acrylonitrile copolymer.
And a compound containing two or more maleimide groups,
10% by weight (more preferably 50 to 10% by weight, optimally 40 to 20% by weight) and 0.3 to 20% by weight of the phenolic antioxidant (more preferably 0.3 to 10% by weight, (Optimally 3 to 7% by weight) and a reaction accelerator such as peroxide within 5% by weight (more preferably 0.1 to 2% by weight, and most preferably 0.1 to 1% by weight). Is dissolved in a suitable organic solvent. By applying this and evaporating the organic solvent to obtain a semi-cured adhesive layer, by bonding to the surface to be bonded and heating,
A preferred first adhesive layer 14 and / or second adhesive layer 18 can be formed.

The butadiene-acrylonitrile copolymer has a weight average molecular weight of 1,000 to 200,000.
Carboxyl group-containing butadiene-acrylonitrile copolymer having 0 and a carboxyl group equivalent of 30 to 10,000, and an acrylic group-containing butadiene-acrylonitrile copolymer having a weight average molecular weight of 1,000 to 200,000 and an acrylic group equivalent of 500 to 10,000. Polymer, epoxy group-containing butadiene-acrylonitrile copolymer having a weight average molecular weight of 1,000 to 200,000 and epoxy group equivalent of 500 to 10,000, butadiene-acrylonitrile copolymer having a weight average molecular weight of 1,000 to 200,000 Polymer and weight average molecular weight 1,0
00 to 200,000 and amino group equivalent 500 to 1
Preferred is one or a mixture of two or more selected from piperazinylethylaminocarbonyl group-containing butadiene-acrylonitrile copolymers having a 000. The average molecular weight is more preferably 3000 to 80000
It is.

In order to reduce the warpage of the ceramic insulating plate due to the change in the volume (mainly shrinkage) of the adhesive layer, the phenolic antioxidant has a thermogravimetric analysis method of reducing the thermogravimetric loss when heated to 200 ° C. It is preferably at most 5%. The rate of thermal weight loss was 10 ° C. /
It is defined as a value measured by raising the temperature in min.

Specific examples of the phenolic antioxidant include:
1,3,5-tris (3,5-di-t-butyl-4-hydroxybenzyl) -s-triazine-2,4,6-
(1H, 3H, 5H) trione: molecular weight 784, weight loss rate 0%, 1,1,3-tris (2-methyl-4-hydroxy-5-t-butylphenyl) butane: molecular weight 54
5, weight loss rate 2.8%, tetrakis [methylene (3,
5-di-t-butyl-4-hydroxyhydrocinnamate)] methane: molecular weight 1178, weight loss rate 0.2
%, 1,3,5-trimethyl-2,4,6-tris (3,5-di-t-butyl-4-hydroxybenzyl)
Benzene: a molecular weight of 775, a weight reduction rate of 0%, and the like can be exemplified. On the other hand, for example, 2,6-di-t-butylphenol has a molecular weight of 206.33 and a weight loss rate of 86.
%.

A filler may be added to the adhesive layers 14 and 18. As the filler, for example, silica, quartz powder, alumina, calcium carbonate, magnesium oxide, diamond powder, mica, kaolinite, fluororesin powder,
Silicone powder, polyimide powder, zircon powder and the like are used. These fillers may be used alone or in combination of two or more. The content of the filler is within 70% by weight of the total solid, preferably in the range of 5 to 40% by weight. If the content is more than 70% by weight, the viscosity during processing decreases, and the adhesive strength and strength after curing decrease.

The thickness of the first adhesive layer 14 is not limited, but is preferably 20 to 200 μm, more preferably 60 to 120 μm, and most preferably 80 to 100 μm.
μm. The thickness of the second adhesive layer 18 is not limited, but is preferably 5 to 50 μm, more preferably 8 to 20 μm, and most preferably 8 to 12 μm. That is, the first adhesive layer 14 is preferably thicker than the second adhesive layer 18. Further, when the warpage generated in the adhesive layer is measured by a warpage rate test method described later, the measured value is desirably 0.03% or less.

In the electrostatic chuck device having the above configuration,
The semi-cured adhesive layer is heat-treated to form the first adhesive layer 14.
When the second adhesive layer 18 is formed, even if the adhesive layers 14 and 18 slightly change in volume, the adhesive layer 1
Since the rubber component, which is the main composition of Nos. 4 and 18, relieves stress by elasticity, the stress applied to the ceramic insulating plate 16 can be reduced. Further, since the adhesive layers 14 and 18 contain a phenolic antioxidant having excellent heat resistance, they absorb radicals generated from the rubber component and can prevent oxidative deterioration of the rubber component for a long period of time. It is possible. As a result, distortion occurs in the ceramic insulating plate 16 or separation occurs at the bonding interface (particularly at the outer peripheral portion) between the ceramic insulating plate 16 and the adhesive layers 14 and 18, and the cooling performance of the wafer W is partially reduced. In the long term, various problems such as deterioration of the flatness of the wafer suction surface, reduction of the wafer suction force, and intense leakage of the cooling helium gas supplied between the wafer suction surface and the wafer become severe. It is possible to reduce the running cost required for component replacement.

Next, a method of manufacturing the electrostatic chuck device of this embodiment will be described. First, the insulating film 22
An electrode layer 20 having a predetermined pattern (refer to FIG. 3) is formed on the entire surface of one surface. In order to form the electrode layer 20 having a complicated pattern, it is possible to form the metal film forming the electrode pattern directly on the insulating film 22. However, it is easier to manufacture the electrode layer 20 by using a photoresist. is there. In this case, a metal film is formed on one entire surface of the insulating film 22 by a vapor deposition method and / or a plating method, and a photoresist layer is formed on the metal film. The photoresist layer may be formed by applying a liquid resist and drying, or may be formed by bonding a photoresist film (dry film) on a metal film by thermocompression bonding.

Subsequently, the photoresist layer is subjected to pattern exposure and development to remove the photoresist at the portion where the metal film is to be dissolved, and then the exposed portion of the metal film is etched, washed, stripped, and dried. The electrode layer 20 having a predetermined shape is formed. These operations may be performed using a known method for forming a photoresist pattern.

After the electrode layer 20 is formed on the insulating film 22, a liquid or film-like adhesive for forming the second adhesive layer 18 is applied to the entire surface of the insulating film 22 on which the electrode layer 20 is formed. Apply so that the surface is flat,
After drying and semi-curing, the second adhesive layer 18 is formed. If necessary, the laminated sheet 17 is obtained by punching according to the shape of the ceramic insulating plate 16.

Next, the ceramic insulating plate 16 is adhered to the metal substrate 10 via the first adhesive layer 14, and the second adhesive layer 1 of the laminated sheet 17 is further placed on the ceramic insulating plate 16.
8 is adhered. When the second adhesive layer 18 contains a thermosetting adhesive, a curing process is performed by performing appropriate heating as needed. As described above, the electrostatic chuck device of the present invention can be manufactured.

When the insulating film 22 becomes fatigued by the wafer processing, the laminated sheet 17 is peeled off from the ceramic insulating plate 16 and a new laminated sheet 17 is bonded. Since the second adhesive layer 18 is thin and hardly deteriorates, it can be easily separated from the ceramic insulating plate 16.
Even if a part remains on 6, it is easy to remove because it is a small amount.

Next, another embodiment of the electrostatic chuck device according to the present invention will be described with reference to FIG. This electrostatic chuck device includes a disk-shaped metal base 10, a first adhesive layer 30 having excellent insulating properties and stress relaxation properties, a disc-shaped ceramic insulating plate 32, a second adhesive layer 36, and an insulating layer. A conductive film 38 is formed in order, and an electrode layer 34 having a fixed pattern is formed on the upper surface of the ceramic insulating plate 32 in a buried state. That is, the electrode layer 3
4 is on the same plane as the upper surface of the ceramic insulating plate 32. The heat medium flow path 12 is formed in the metal substrate 10 as in the above embodiment.

FIG. 5 shows a more specific configuration of this embodiment. The apparatus of this embodiment also has a through hole 24 for elevating the wafer and an electrode layer, similarly to the embodiment of FIG. Elements 25 to 28 for supplying power to the power supply 34 are formed. The planar shape of the electrode layer 34 may be similar to that of the electrode layer 20 shown in FIG. 3, but is not limited. A gas passage (not shown) may be formed as in the above embodiment.

The material of the electrode layer 34 may be the same as in the above embodiment. The electrode layer 34 may be a stamped and formed metal foil, a conductor formed by firing a conductive paste, or vapor deposition and / or deposition on the upper surface of the ceramic insulating plate 32.
Alternatively, it may be a plated metal deposited film or a plated metal film. In particular, silver, platinum, palladium, molybdenum, magnesium, tungsten and alloys thereof are preferable because they can be handled in a paste form or a powder form and have excellent workability and printability. Among them, palladium alloys have good conductivity and workability. is there. When the electrode layer 34 is thick, a concave portion having a pattern of the electrode layer 34 is formed on the upper surface of the ceramic insulating plate 32, and the electrode layer 3 is formed therein.
4 are formed. When the concave portion is formed, if there is a step between the ceramic insulating plate 32 and the electrode layer 34, the adhesion of the wafer W is deteriorated. It is preferable to make the upper surface smooth by polishing or the like.

The thickness of the electrode layer 34 is not limited, but may be relatively thick in this embodiment, and may be 0.05 to 2 mm.
And more preferably 0.05 to 1 m
m. When the electrode layer 34 is very thin, the electrode layer 34 may be directly formed on the surface of the ceramic insulating plate 32 without forming a recess on the surface.

Insulating film 38 and second adhesive layer 3
Reference numeral 6 denotes a laminated sheet 35 that is peeled off from the ceramic insulating plate 32 and the electrode layer 34 and replaced when the insulating film 38 is worn. The material and thickness of the insulating film 38 are preferably in the range of 20 to 75 μm, similarly to the insulating film 22 of the above embodiment, and 40 to 60 μm.
Is particularly preferred.

The material of the ceramic insulating plate 32 may be the same as that of the ceramic insulating plate 16 of the above embodiment. The thickness of the ceramic insulating plate 32 is not limited. However, from the viewpoint of securing sufficient durability while releasing heat from the surface to be attracted, the thickness is 0.5 to 8 mm.
mm is preferable, and more preferably 0.5 to 4 m
m, optimally 0.5-1 mm.

Metal substrate 10, first adhesive layer 30, ceramic insulating plate 32, second adhesive layer 36, insulating film 3
8 may have a plurality of gas passages (not shown) that are open to the wafer suction surface. The adhesive for forming the first adhesive layer 30 and the second adhesive layer 36 may be the same as in the previous embodiment. Although the thickness of the first adhesive layer 30 and the second adhesive layer 36 is not limited, the thickness of the first adhesive layer 30 is preferably 20 to 200 μm, more preferably 50 to 150 μm, and 80 to 120
μm. The thickness of the second adhesive layer 36 is 5 to 100 μm.
m, more preferably 5 to 50 μm
Optimally, it is 10 to 30 μm.

In the electrostatic chuck device of this embodiment, the same effects as those of the above embodiment can be obtained, and the second adhesive layer 36
Is thin, it is easy to completely remove the adhesive from the ceramic insulating plate 32 and the electrode layer 34 by washing or the like when the laminated sheet 35 is peeled and a new laminated sheet 35 is stretched. Since no electrode is formed on the laminated sheet 35, there is an advantage that the work of replacing the laminated sheet 35 can be easily performed.

Next, a method of manufacturing the electrostatic chuck device of this embodiment will be described. First, the ceramic insulating plate 3
2 is ground to form a concave portion having a constant depth that forms a pattern of the electrode layer 34. Next, the electrode layer 3 is placed in the recess.
4 is formed. For this purpose, a plate-like electrode layer 34 formed in advance by punching or the like may be fitted into the concave portion and adhered, or the electrode layer 34 may be formed in the concave portion by vapor deposition or plating. In order to form the conductive paste, a conductive paste containing a metal fine powder such as platinum palladium or silver is applied to the grinding portion by screen printing or the like, and then heat-cured and, if necessary, fired at several hundred degrees Celsius. Then, the electrode layer 34 is formed. If necessary, the surface on which the electrode layer 34 is formed is smoothed by polishing or the like. When the ceramic insulating plate 32 is manufactured, a concave portion having a predetermined pattern may be formed in the ceramic insulating plate before firing, and a conductive paste may be printed or applied, followed by firing.

Next, the lower surface of the ceramic insulating plate 32 is
It adheres to the metal substrate 10 via the adhesive layer 30. The through holes 25 are desirably formed in the ceramic insulating plate 32 and the metal substrate 10 in the thickness direction in advance. The power supply member 27 is connected to the electrode layer 34, and the through holes 25 are sealed with the insulator 28. I do. Next, the second adhesive layer 36 in a semi-cured state of the laminated sheet 35 is adhered to the upper surfaces of the ceramic insulating plate 32 and the electrode layer 34, and the second adhesive layer 36 is heated to form a second adhesive layer 36.
The adhesive layer 36 is cured.

By processing the wafer W, the insulating film 38 is formed.
Is fatigued, the laminated sheet 35 is placed on the ceramic insulating plate 3.
2 and a new laminated sheet 35 is bonded. Second
Since the adhesive layer 36 is thin, it can be easily separated from the ceramic insulating plate 32. Even if a part of the adhesive layer 36 remains on the ceramic insulating plate 32, it can be easily removed because the amount is small. Further, in this embodiment, since the electrode layer 34 is not included in the laminated sheet 35, the replacement cost of the laminated sheet 35 can be reduced.

[0049]

[Example 1]: First adhesive: acrylonitrile-butadiene copolymer having a piperazinylethylaminocarbonyl group at both terminals ("Hycar ATBN" manufactured by Ube Industries, Ltd.) (m = 83.5) , N = 1
80 parts by weight of 6.5, a weight average molecular weight of 3600, and an acrylonitrile content of 16.5%) were dissolved in a toluene / methyl ethyl ketone mixture (1: 1), and
20 parts by weight of a maleimide compound represented by the following formula (I), 0.1 part by weight of lauroyl peroxide (manufactured by NOF Corporation), and tetrakis [methylene (3,5- 1 part by weight of di-t-butyl-4-hydroxy (dihydrocinnamate)] methane (Adekastab AO-60, manufactured by Asahi Denka Kogyo Co., Ltd.) was mixed and dissolved in tetrahydrofuran, and a liquid adhesive having a solid content of 40% by weight was mixed. An agent was prepared.

[0050]

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Example 2 Second Adhesive Acrylonitrile butadiene copolymer having a piperazinylethylaminocarbonyl group at both ends ("Hycar ATBN" manufactured by Ube Industries, Ltd.) (m = 83.5, n = 1
6.5, a weight average molecular weight of 3,600, and an acrylonitrile content of 16.5%) were mixed with 50 parts by weight of an acrylonitrile butadiene copolymer having a piperazinylethylaminocarbonyl group at both terminals represented by the following formula (II) ( m = 8
0, n = 20, weight average molecular weight 10,000, acrylonitrile content 20%), and dissolved in a toluene / methyl ethyl ketone mixture (1: 1). Maleimide compound 2 shown
0 parts by weight, lauroyl peroxide (manufactured by NOF CORPORATION)
1 part by weight, and tetrakis [methylene (3,5-di-
1 part by weight of t-butyl-4-hydroxy (dihydrocinnamate)] methane (Adekastab AO-60, manufactured by Asahi Denka Kogyo Co., Ltd.) was mixed and dissolved in tetrahydrofuran to obtain a liquid adhesive having a solid content of 40% by weight. Prepared.

[0052]

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Example 3 Third Adhesive The tetrakis [methylene (3,5-di-tert-butyl-4-hydroxy (dihydrocinnamate)] methane used in Example 1 was replaced with 1,3 , 5-Tris (3,5-di-t
Example 1 except that -butyl-4-hydroxybenzyl) -s-triazine-2,4,6- (1H, 3H, 5H) trione ("Adeka Stab AO-20" manufactured by Asahi Denka Kogyo KK) was used. A liquid adhesive was prepared in the same manner as described above.

Example 4 Fourth Adhesive The tetrakis [methylene (3,5-di-t-butyl-4-hydroxy (dihydrocinnamate)] methane used in Example 1 was replaced with 1,3 , 5-Trimethyl-2,4,6
-Tris (3,5-di-t-butyl-4-hydroxybenzyl) benzene (ADK STAB A manufactured by Asahi Denka Kogyo KK)
O-330 "), except that the liquid adhesive was prepared in the same manner as in Example 1 above.

Example 5 Fifth Adhesive The amount of tetrakis [methylene (3,5-di-t-butyl-4-hydroxy (dihydrocinnamate)] methane used in Example 1 was determined as follows. A liquid adhesive was prepared in the same manner as in Example 1 except that the amount was changed from 1 part by weight to 10 parts by weight.

Example 6: Sixth adhesive The maleimide compound used in Example 1 was replaced by the following formula (II)
A liquid adhesive was prepared in the same manner as in Example 1 except that the maleimide compound shown in I) was used. In addition, P is an integer of 0-7.

[0057]

Embedded image

Example 7: Seventh adhesive Acrylonitrile-butadiene copolymer having a piperazinylethylaminocarbonyl group at both terminals ("Hycar ATBN" manufactured by Ube Industries, Ltd.) (m = 83.5, n = 1
6.5, a weight average molecular weight of 3,600, an acrylonitrile content of 16.5%) and an acrylonitrile-butadiene copolymer having vinyl groups at both ends ("Hycar VTBN" manufactured by Ube Industries, Ltd.) (m = 83.5, n
= 16.5, weight average molecular weight 3600, acrylonitrile content 16.5%) in a toluene / methyl ethyl ketone mixture (1: 1), and the solution was added with the above formula (I). 20 parts by weight of the maleimide compound shown, 0.1 parts by weight of α-α′bis (t-butylperoxy-m-isopropyl) benzene (manufactured by NOF Corporation), and tetrakis [methylene (3,5-di-t-butyl-) 4-hydroxy (dihydrocinnamate)] methane (Adecastab AO-60, manufactured by Asahi Denka Kogyo KK) is mixed in 1 part by weight, dissolved in tetrahydrofuran, and solid content is 40% by weight.
Was prepared.

Example 8 Eighth Adhesive Acrylonitrile-butadiene copolymer having a vinyl group ("Hycar" manufactured by Ube Industries, Ltd.) used in Example 7
Acrylonitrile-butadiene copolymer having carbonyl groups at both ends ("HycarCTBN" manufactured by Ube Industries, Ltd.) (m = 2.7, n = 1, instead of VTBN))
Weight average molecular weight 3500, acrylonitrile content 1
An adhesive was prepared in the same manner as in Example 7, except that 40 parts by weight (6.5%) was used.

Example 9 Ninth Adhesive Acrylonitrile-butadiene copolymer having a piperazinylethylaminocarbonyl group at both ends (“Hycar ATBN” manufactured by Ube Industries, Ltd.) (m = 83.5, n = 1
6.5, a weight average molecular weight of 3,600, an acrylonitrile content of 16.5%) and 70 parts by weight of bisphenol A type
(10 parts by weight of "Epicoto 828" manufactured by Yuka Shell Epoxy Co., Ltd., and a mixed solution of toluene / methyl ethyl ketone (1: 1)
And 20 parts by weight of the maleimide compound represented by the above formula (I), α-α'bis (t-butylperoxy-m-isopropyl) benzene (manufactured by NOF Corporation) 0.1
Parts by weight, 0.3 parts by weight of dicyandiamide, and tetrakis [methylene (3,5-di-t-butyl-4-hydroxy (dihydrocinnamate)]] methane (“Adeka Stab AO-60” manufactured by Asahi Denka Kogyo KK). One part by weight was mixed and dissolved in tetrahydrofuran, and the solid content was 40% by weight.
Was prepared.

Example 10: Tenth adhesive 100 parts by weight of a butadiene-acrylonitrile copolymer (weight average molecular weight 250,000, acrylonitrile content 27%), pt-butylphenol type resole phenol resin (Showa "CKM1282" manufactured by Kobunshi Co.)
20 parts by weight of a novolak epoxy resin (20 parts by weight of "EOCN-1020" manufactured by Nippon Kayaku Co., Ltd .; 25 parts by weight of a maleimide compound represented by the formula (I); 1,3-bis (3-aminopropyl) 5 parts by weight of -1,1,3,3-tetramethyldisiloxane, 0.1 part by weight of α-α′-bis (t-butylperoxy-m-isopropyl) benzene (manufactured by NOF CORPORATION), and tetrakis [ Methylene (3,5-
Di-t-butyl-4-hydroxy (dihydrocinnamate)] methane (“ADK STAB AO-
60 ") was dissolved in tetrahydrofuran to prepare a liquid adhesive having a solid content of 30% by weight.

Example 11 Eleventh Adhesive Acrylonitrile-butadiene copolymer having piperazinylethylaminocarbonyl groups at both ends ("Hycar ATBN" manufactured by Ube Industries, Ltd.) (m = 83.5, n = 1
6.5, a weight average molecular weight of 3,600, and an acrylonitrile content of 16.5%) were dissolved in a toluene / methyl ethyl ketone mixture (1: 1), and
40 parts by weight of the maleimide compound represented by the formula (I), 0.1 part by weight of lauroylperoxide (manufactured by NOF CORPORATION), and tetrakis [methylene (3,5-di-t-butyl-4-hydroxy) (Dihydrocinnamate)] 1 part by weight of methane (“ADK STAB AO-60” manufactured by Asahi Denka Kogyo Co., Ltd.) and 25 parts by weight of a spherical alumina filler having an average particle size of 5 μm were mixed, and dissolved in tetrahydrofuran.
A liquid adhesive having a solid content of 40% by weight was prepared.

[Comparative Example 1]: First adhesive for comparison Tetrakis [methylene (3,5) used in Example 1
-Di-t-butyl-4-hydroxy (dihydrocinnamate)] An adhesive having a solid content of 40% by weight was prepared in the same manner as in Example 1 except that methane was not used.

Comparative Example 2 Second adhesive for comparison Tetrakis [methylene (3,5) used in Example 1
-Di-t-butyl-4-hydroxy (dihydrocinnamate)] In the same manner as in Example 1 except that L-ascorbic acid was used instead of methane, the solid content was 40% by weight.
Was prepared.

[Comparative Example 3]: Third adhesive for comparison epoxy acrylate (“R-551” manufactured by Nippon Kayaku Co., Ltd.)
100 parts by weight of benzoyl peroxide and 1 part by weight of
The adhesive was dissolved in a toluene / methyl ethyl ketone mixture (1: 1) to prepare an adhesive having a solid content of 40%.

[Evaluation Experiment 1]: The difficulty of peeling from the ceramic insulating plate was evaluated. Using the adhesives of Examples 1 to 11 and Comparative Examples 1 to 3, laminated sheets 17 for an electrostatic chuck device shown in FIG. First, aluminum is vapor-deposited on a large number of insulating films made of polyimide film (trade name: Kapton, manufactured by Du Pont-Toray Co., Ltd.) having a thickness of 50 μm to a thickness of 500 angstroms, and an electrode layer 20 having a shape as shown in FIG. Is formed, the adhesives of Examples 1 to 11 and Comparative Examples 1 to 3 are applied to the electrode forming surface so that the thickness after drying becomes 20 μm, and these are dried and heated at 150 ° C. It was semi-cured by heating for 5 minutes. The same adhesive was again applied on these adhesive layers so that the thickness after drying became 20 μm, dried and semi-cured to form a semi-cured adhesive layer having a total of 40 μm.

Each of the laminated sheets thus obtained was subjected to
Affixed to a ceramic insulating plate with a flat surface and a thickness of 3 mm × 3 mm (electrodes are not formed).
By performing a step cure at 50 ° C., the second adhesive layer 36
Was cured.

The thus obtained laminated body of the ceramic insulating plate and the laminated sheet was placed in a heat cycle test apparatus, heated to 150 ° C. and held for 30 minutes, and then cooled to -40 ° C.
The cycle of rapidly cooling and holding for 30 minutes was repeated 60 times, and after returning to room temperature, it was visually checked whether or not the adhesive layer had peeled off.

As a result, no peeling occurred in the laminated sheets using the adhesives of Examples 1 to 11 and Comparative Examples 1 and 2, but in the laminated sheets using the adhesive of Comparative Example 3, the ceramic insulating material was used. It was partially peeled from the board.

Example 12 An alumina ceramic insulating plate having a thickness of 2 mm (trade name: AL manufactured by Toshiba Ceramics Co., Ltd.)
-16) One surface is set to a depth of 0.1
A concave portion of mm was formed by grinding. Next, a silver-palladium alloy paste is created and applied to the ground portion of the insulating plate.
After heating to cure the electrode layer, the surfaces of the ceramic insulating plate and the electrode layer were polished and smoothed.

Next, on the non-electrode surface of the ceramic insulating plate,
The adhesive of Example 1 was applied so that the thickness after drying became 20 μm, dried at 150 ° C. for 5 minutes, and bonded to a metal substrate. At this time, a through hole was formed in the metal substrate and the ceramic insulating plate in the thickness direction, and a voltage could be applied between the electrode layer and the metal substrate through a conductive member in the through hole.

Next, the above-mentioned adhesive was applied to one surface of a 50 μm-thick insulating polyimide film (trade name: Kapton, manufactured by Dupont Toray Co., Ltd.) so that the thickness after drying became 20 μm, and the coating was applied at 150 ° C. for 5 minutes. After drying to form a second adhesive layer, the second adhesive layer is bonded to a ceramic insulating plate on a metal base, and is subjected to a step curing process at 80 ° C. to 150 ° C. for 5 hours to be bonded, and the 8 inch diameter static electrode according to the present invention is bonded. An electrostatic chuck device having an electric chuck surface was manufactured.

The device of Example 12 was placed in the same heat cycle test device as in Evaluation Experiment 1, and it was visually confirmed whether or not the adhesive layer was peeled off under the same conditions. As a result, no peeling of the adhesive layer occurred in the device of Example 12.

[Evaluation Experiment 2]: The elongation and the warpage were evaluated. The adhesives of Examples 1 to 11 and Comparative Examples 1 to 3 were applied to one surface of a polyethylene terephthalate film (thickness: 37 μm) that had been subjected to a release treatment in advance, and dried at 120 ° C. for 5 minutes to obtain a 20 μm thick film. Forming an adhesive layer,
An adhesive sheet was used.

Further, two polyethylene terephthalate films each having an adhesive layer formed by the adhesive of Example 1 were adhered to each other, and one of the films was peeled off.
An adhesive sheet having an adhesive layer having a thickness of 40 μm was produced (Example 13).

After heating each of the above adhesive sheets at 180 ° C. for one hour to cure the adhesive, all the films were peeled off, and the cured adhesive layer was cut into a rectangle of 10 mm × 100 mm. (Tensilon manufactured by Shimadzu Corporation) and 50m in the longitudinal direction of the adhesive layer
The elongation was measured immediately before the adhesive layer was cut by pulling at m / min. Table 1 shows the results.

Examples 1 to 11 and Comparative Examples 1 to 3
All the films were peeled off from the adhesive sheet having the adhesive layer formed thereon and the adhesive sheet of Example 13, and only the adhesive layer was coated with a borosilicate glass of 76 mm × 52 mm × 0.9 mm and 76 mm × 52 mm × 5 mm After sandwiching it between the aluminum plate and laminating with a laminating machine,
The adhesive layer was cured by heating at 120 ° C. for 2 hours. After the temperature was returned to room temperature, the depth (μm) of the warpage generated on the glass surface was measured with a digital depth microscope. Further, (warp depth) / (diagonal length of glass) was obtained as a warpage rate (%). Table 1 shows the results.

[0078]

[Table 1]

As is evident from Table 1, the adhesive layers of Examples 1 to 11 and 13 according to the present invention had much higher elongation and rich elasticity than Comparative Examples 1 to 3. Further, since the stress generated at the time of curing was small, the warpage generated on the glass surface was small. According to this result, the warpage due to the difference in thermal expansion (or contraction) between the metal substrate and the ceramic plate can be absorbed, and the volume change due to the temperature change of the adhesive layer is small, so that the ceramic plate and / or the wafer are attracted. It could be expected that the warpage of the surface could be improved and that the effect of preventing damage to the ceramic insulating plate could be obtained.

[0080]

As described above, according to the electrostatic chuck device of the present invention, when the adhesive layer in the semi-cured state is heat-treated to form the adhesive layer, the adhesive layer slightly changes in volume. Even if it does, the stress applied to the ceramic insulating plate can be reduced because the rubber component, which is the main composition of the adhesive layer, relieves stress by elasticity. In addition, since the adhesive layer contains a phenolic antioxidant having excellent heat resistance, it can absorb radicals generated from the rubber component and prevent oxidative deterioration of the rubber component for a long time. . As a result, distortion occurs in the ceramic insulating plate, partial separation occurs at the bonding interface between the ceramic insulating plate and the adhesive layer, and the cooling property of the object to be adsorbed is reduced, and the flatness of the adsorption surface is deteriorated. It is possible to prevent various problems such as a decrease in suction force over a long period of time.

Further, according to the laminated sheet for an electrostatic chuck and the adhesive for an electrostatic chuck sheet according to the present invention, even when the adhesive layer slightly changes in volume when the adhesive layer is heated and bonded. Since the rubber component, which is the main composition of the adhesive layer, relieves stress by elasticity, it is possible to reduce effects such as distortion of the adherend and reduction in flatness of the sheet surface. In addition, since the adhesive layer contains a phenolic antioxidant having excellent heat resistance, it efficiently absorbs radicals generated from the rubber component even at a high temperature and prevents oxidative deterioration of the rubber component for a long time. It is possible. As a result, the object to be bonded may be distorted, the bonding interface may be partially separated, and the cooling property of the object to be adsorbed may be reduced, or the flatness of the adsorbing surface may be deteriorated to lower the adsorbing force. It is an excellent effect that various problems can be prevented over a long period of time.

[Brief description of the drawings]

FIG. 1 is a sectional view of an embodiment of an electrostatic chuck device according to the present invention.

FIG. 2 is a sectional view of another embodiment of the electrostatic chuck device according to the present invention.

FIG. 3 is a plan view of another embodiment of the electrostatic chuck device according to the present invention.

FIG. 4 is a sectional view taken along line IV-IV in FIG.

FIG. 5 is a sectional view of another embodiment of the electrostatic chuck device according to the present invention.

FIG. 6 is a cross-sectional view of an example of a conventional electrostatic chuck device.

FIG. 7 is a cross-sectional view of an example of a conventional electrostatic chuck device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Metal substrate 12 Heat medium flow path 14, 30 1st adhesive layer 16, 32 Ceramic insulating plate 18, 36 2nd adhesive layer 20, 34 Electrode layer 22, 38 Insulating film 24 Through-hole 27 Power supply member

Claims (11)

[Claims] 1. A metal base, an adhesive layer provided on the metal base, and a ceramic insulating plate made of ceramic provided on the adhesive layer, wherein the adhesive layer comprises a rubber component. And a phenolic antioxidant, wherein the rubber component is one or more selected from a butadiene-acrylonitrile copolymer, an olefinic copolymer, and a polyphenylether copolymer. Characteristic electrostatic chuck device. 2. A metal substrate, a first adhesive layer provided on the metal substrate, a ceramic insulating plate provided on the first adhesive layer, and a ceramic insulating plate provided on the ceramic insulating plate. A second adhesive layer, an insulating film provided on the second adhesive layer, and an electrode provided between the second adhesive layer and the insulating film,
At least one of the first adhesive layer and the second adhesive layer contains a rubber component and a phenolic antioxidant, and the rubber component is a butadiene-acrylonitrile copolymer, an olefin copolymer, and An electrostatic chuck device comprising one or more kinds selected from polyphenyl ether copolymers. 3. The thickness of the electrode is 300 Å to 10 μm, and the thickness of the insulating film is 20 to 75 μm.
μm, the thickness of the ceramic insulating plate is 0.3 to 8 mm,
The thickness of the first adhesive layer is 20 to 200 μm,
3. The electrostatic chuck device according to claim 2, wherein the thickness of the adhesive layer is 5 to 50 [mu] m. 4. A metal substrate, a first adhesive layer provided on the metal substrate, a ceramic insulating plate provided on the first adhesive layer, and a ceramic insulating plate provided on the ceramic insulating plate. A second adhesive layer, an insulating film provided on the second adhesive layer, and an electrode embedded on the upper surface of the ceramic insulating plate. 2 At least one of the adhesive layers contains a rubber component and a phenolic antioxidant, and the rubber component is selected from a butadiene-acrylonitrile copolymer, an olefinic copolymer, and a polyphenylether copolymer. An electrostatic chuck device characterized by one or more types. 5. The thickness of the electrode is 0.05 to 2 mm, the thickness of the insulating film is 20 to 75 μm, the thickness of the ceramic insulating plate is 0.5 to 8 mm, and the thickness of the first adhesive layer is The electrostatic chuck device according to claim 4, wherein the thickness is 20 to 200 m, and the thickness of the second adhesive layer is 5 to 100 m. 6. The electrostatic chuck device according to claim 1, wherein the phenolic antioxidant is a hindered phenolic antioxidant. 7. The hindered phenolic antioxidant is a substance having three or more phenol groups in which two or more t-butyl groups are bonded in one molecule, and having a molecular weight of 700 or more. 7. The electrostatic chuck device according to claim 6, wherein: 8. The electrostatic chuck device according to claim 6, wherein the hindered phenolic antioxidant has a thermal weight loss rate of 5% or less when heated to 200 ° C. 9. An insulating film, comprising: an insulating film; and an adhesive layer provided on at least one surface of the insulating film, wherein the adhesive layer contains a rubber component and a phenolic antioxidant; The laminated sheet for an electrostatic chuck, wherein the component is at least one selected from a butadiene-acrylonitrile copolymer, an olefin-based copolymer, and a polyphenylether copolymer. 10. The laminated sheet for an electrostatic chuck according to claim 9, wherein an electrode is fixed to the insulating film. 11. An adhesive for an electrostatic chuck sheet containing a rubber component and a phenolic antioxidant, wherein the rubber component is a butadiene-acrylonitrile copolymer, an olefin copolymer, and a polyphenyl ether. One or more selected from copolymers,
The phenolic antioxidant is a substance having three or more phenol groups in which two or more t-butyl groups are bonded in one molecule and having a molecular weight of 700 or more. Adhesive for electro chuck sheet.